pionneer dual layer burner

im only new to this site so bear with me please.ive been burning dvds for awhile with no problems. changed my burner from pioneer 108 to new109 and now i cannot create iso files from dvds with decrypt. decrypt goes 98% then says "not enough space" but i have 13gig. firmware version is latest for burner. i can do vobs but not iso.can anyone help me as im desperate to burn again.thankx